1. Field of the Invention
The present invention relates to an optical apparatus, such as a camera, having a flash-illumination-area controlling device for controlling the illumination area of flash light.
2. Description of the Related Art
A conventional type of camera has the disadvantage that during photography using a flash unit, if a subject is positioned close to the camera, the flash unit cannot illuminate the entire subject.
Such a disadvantage will be described below with reference to FIG. 20.
As shown in FIG. 20, a photographic area 34 of a camera 31 and an illumination area 33 of a flash unit 32 do not completely coincide with each other. If a subject is located at a position 35, the illumination area 33 can cover the entire photographic area 34, but if the subject is located at a position 36, the photographic area 34 will contain a portion which is not covered by the illumination area 33 (hereinafter referred to as "insufficiently illuminated portion" or similar). It is readily understood that the size of the insufficiently illuminated portion becomes larger as the focal length of a lens becomes shorter through zooming (for example, when the focal length is changed from 50 mm to 35 mm with a zoom lens set to its wide-angle side). of course, even if the subject is located at the closest-distance position, the problem of the insufficient illumination can be solved by enlarging an illumination angle so that the illumination area 33 can cover the entire photographic area 34 (as indicated by two-dot chain lines 30). However, if the illumination angle is enlarged in this manner, the illumination angle becomes excessively large with respect to the photographic area 34 and efficient illumination with flash light is not effected, that is to say, it is impossible to effectively utilize flash light.